1. Field of the Invention
The present invention relates to a rubber-like molded product with a support frame, a method of manufacturing the same, and a method of fitting a rubber-like molded product, and more particularly to a rubber-like molded product which can be used as a sealing material, a damping material, or the like for various mechanical components, a method of manufacturing the same, and a method of fitting the same.
2. Description of the Related Art
Conventionally, in order to provide a predetermined sealing effect, a damping effect or the like between component parts of various types of machines, a method is adopted in which a sealing material such as a gasket formed by, for instance, an annular rubber-like molded product is interposed between such component parts. As a method of fabricating an integrally formed product by fitting or bonding such a rubber-like molded product to a member to which the rubber-like molded product is fitted (herein and in the appended claims this member will be referred to as a fitted member), such as a coupling member constituting a split-type mechanical component, the following method is generally adopted. The rubber-like molded product is molded in advance by injection molding or press molding (compression molding), and, by means of handling equipment, this rubber-like molded product is press fitted into a groove or the like formed at a predetermined position of the fitted member or made integral therewith by using a predetermined adhesive agent.
In addition, under restricted conditions such as in a case where the shape of the rubber-like molded product is relatively simple, or in a case where the shapes of the rubber-like molded product and the fitted member conform to each other with a high degree of accuracy, the rubber-like molded product is, in some cases, fitted automatically to the fitted member by using an automated machine having an appropriate pushing jig or the like.
Furthermore, a method in which the integrally molded product is obtained by an insert molding method is also adopted in some other cases. This is a method in which the fitted member is placed in advance in a mold, and an injection material is injected into the mold in this state so as to obtain the integrally molded product. In addition, a method is also reported in which, by means of a double-injection molding method, after a plastic member is molded into a predetermined shape by primary molding, a secondary cavity is provided by replacing a part of the mold or by using a core back method, and the rubber-like molded product is formed by secondary molding, thereby manufacturing an integrally molded product.
It should be noted that when the rubber-like molded product is formed, it is unavoidable for a thin burr to be formed along a parting plane of the mold in the periphery of the rubber-like molded product, so that a deburring operation is required for the commercialization of the rubber-like molded product itself. Since the shape of the rubber-like molded product itself and the shape of the burr are irregular, it is difficult to automate this operation. Accordingly, the actual situation is such that the deburring operation is effected by handling equipment.
However, since the above-described method in which the rubber-like molded product is fitted to the fitted member by means of handling equipment is basically based on a manual operation, this method lacks in the efficiency in mass production, and results in higher cost. Also, variation in the quality of the product such as a fitting error is liable to occur, and expertise of the operator is required.
In addition the automatic fitting of a rubber-like molded product which is implemented in very restricted cases has had the drawback that it is restricted to cases where the shape of the rubber-like molded product is simple and the shapes of the rubber-like molded product and the fitted member conform to each other to fit in a simple manner. Further, under a condition where the site of fabrication of the rubber-like molded product and the site of fitting the rubber-like molded product to the fitted member differ, there arises the need to package the rubber-like molded product and transport it to the fitting site. In this case, however, deformation such as twisting is liable to occur due to vibrations or load applied to the rubber-like molded product, with the result that there has been a problem that the rubber-like molded product cannot be accurately placed on the automated machine for automatic fitting.
Furthermore, with the method of manufacturing an integrally molded product combining the rubber-like molded product and the fitted member by means of the insert molding method or the double-injection molding method, restrictions are imposed on the design of the fitted member to be inserted (the primary molded product in the double-injection molding method). Included among these restrictions are high accuracy in its shape for integration, the need to secure a large area for the arrangement of the rubber-like molded product, and the need to take into consideration the structure for integration. For this reason, if the shape of the product with the conventional rubber-like molded product fitted is adopted as it is, it is almost impossible to implement the above-described molding method. Hence, there has been a problem in that a special design is required in adopting the above-described molding method.
To overcome the instability of the shape-retaining characteristic of the rubber-like molded product in a case where the rubber-like molded product is singly used, as shown in FIG. 17, a so-called carrier gasket 50, in which a shape supporting member 51 and a gasket 52, i.e., a rubber-like molded product, are formed integrally, has been put to commercial use. This carrier gasket 50 is molded such that the shape supporting member 51 is inserted in a mold, and the gasket 52 is formed by insert molding through a plurality of through holes 53 formed in the thicknesswise direction of the shape supporting member 51, i.e., vertically in the drawing.
In this case, however, it is essential to use the shape supporting member 51 as a part of the constituent elements of the product. Not only does this result in an increase in cost, but also it makes it difficult to adopt an O-ring structure and results in a decline in pressure resistance and the like. The fitted member to which this carrier gasket 50 is fitted must have a shape conforming thereto. Therefore, the restrictions imposed on the product design still remain.
Since the operation of deburring the rubber-like molded products results in increased cost due to a decline in mass-production efficiency, the mold is in some cases fabricated such that its parting line surface is finished to high accuracy so as to avoid a burr. However, there have been drawbacks in that the fabrication of such a mold requires a very high level of expertise, and that the mold thus fabricated lacks in versatility and leads to an even higher cost.